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TBI swap starting issue

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Dogman12

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Nov 12, 2006
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Easthamptom Ma. 01027
I swaped an 89 tbi engine out of a blazer with the complete harness up to the fuse block, I have everything wired and have power where it should be, orange battery power, pink and black on with key, light purple power when cranking. Fuel pump (carter p50001) gets power after cranking but not initial 2 sec spurt. I checked the pnk/blk and it has power with the key to the egr, injectors etc. The pink coil wire has power, the ecm has power. The injectors are not giving out any fuel and it will not start with starting fluid. I put in a new fuel pump reley and changed the coil and it still want fire. Is there anthing else that would not allow fuel and spark? I can not figure out why I dont get to 2 sec delay to the fuel pump. Oh I put this in an 85 Jimmy, I have manual tranny with no options, I took the cruise control and the auto tranny wires off the harness. i did buy an ecm for an manual tranny. could it be a nuetral/park safety switch issue I double checked and all the ecm grounds are good. Would the ICM inhibit spark and fuel? I have been searching for answers and hate to keep throwing parts at it.

Thanks
Jesse
 
Yes, ECM won't pulse the injectors without signal that the ignition is cranking.

http://coloradok5.com/forums/showthread.php?t=141717&highlight=troubleshooting

Crank no run is what you need. Figure out how to do the tests, don't assume if you can't test it. Injector pulse is easily tested with a 12V bulb from the dash, one wire to each contact on the bulb, end of each wire into the injector plug. Cranking engine, lightbulb should blink. Sounds like it won't, but test if you get that far in the diagram.
 
I tested the small purple wire going to the inside( block side) of the starter and crank signal to ecm, I have an in line fuse for it 3 amp as required so i could plug into the line with a test light that i put up on the cowl and it lit only during crank. While searching I see alot of issues witht the pick up coil in and module in the distributer, do you have any sight on these parts? What would cause the 2 second prime of the pump not to occur? This is my first time working with FI your help is much appreciated.

Jesse
 
There should be a 10 guage wire that goes from the + battery to the alternator. The alternator terminal is used as a junction for another wire(s). It feeds the switched hot circut that powers the ignition and a few other things I think it does the delay in the fuel pump too.. Is that wire hooked up right?
 
I will check, the wires from the 85 alt went to the starter not the juntion block, I wired both. one to the starter and one to the junction block maybe it is messing something up. Thanks Jesse
 
USUALLY in swaps like this, it's a wire (or multiple) that aren't getting power when they need it. Double, triple check all of that first. The troubleshooting guides sometimes won't lead you down that path.
 
If the fuel pump is not turning on with the key (except when cranking), but the fuel pump does run while cranking then the ECM is not telling the fuel pump relay to turn the pump on.

Or your relay is bad or hooked up wrong and the pump is only turning on while cranking because the oil pressure switch bypassing the relay as it's designed to do in that situation.
 
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I double checked my wiring, I did add a ground from the engine to the frame, no help. Yes the oil pump switch is turing the fuel pump on not the reley. I did put a new reley in but no help, I did check for power while i had it open and the orange wire had power. I was going to get rid of the oil presure switch and cut the harness but after all the reading I did i wired it back in, I did run two seperate power wires, they come from the same source just into a fuse block and then one to the switch and the other to the ecm, does this matter? I checked th pins in the ecm and there was power where it should have it. So if the fuel pump is running off the oil presure switch it should start? I never unhooked the whole harness from the engine just took the cruise and auto tranny wires out and wired power where i thought it should be. I did find a tan and white wire that looks just like the wire for the fuse pump coming from the ecm, it goes the route of the cts and is joined with th ects ground on a factory loop and grounded. I could not finf this wire on any diagram? I am at a loss, getting tired and working outside is no fun. I appreciate the responses.
 
So you're saying that even though the fuel pump relay is getting power, it't not sending that power to the fuel pump?

I think you need some way to confirm the output of the relay is working. The output is a light brown wire with a white stripe.
 
Yes the orange wire to the fuel pump reley is hot but it appears the oil switch is powering the pump. The reley is new and the wiring for the reley is from the factory harness, no cuts or splicing. Thanks Jesse
 
The orange wire is the supply wire to the relay. I'm saying you need to figure out if the "output" of the relay is getting 12v when it should. That will tell you if the relay is working or not. You're only guessing at the problem until you confirm what's causing the relay to not turn the fuel pump on.
 
I understand the wires, and I am guessing. like I said the oil switch is powering the pump, I put in a new relay, my question would be what would tell the ecm not to signal the relay to turn on. is it a bad ecm, icm, pick up coil etc. I have double checked my power leads, grounds and have done tons of internet searching.
Thanks
Jesse
 
question would be what would tell the ecm not to signal the relay to turn on
Click to expand...

So you checked the "input" to the relay to confirm it's NOT getting 12V for 2 seconds after turning the key on?

I thought you said it was getting 12v.

Brian
 
The fuel relay has an orange wire for a power source, this is battery power so it is always hot. From my understanding the ignition module or the ecm should send a signal to the relay i think through a green and white wire ( from the ecm)and that should open the relay to allow power to the pump. The ecm I have is in a black case not silver so it may be after market it was an ebay purchase for 87-95 MT 350 truck or van I checked it to make sure it had a prom and it did. The engine itself came from an 89 blazer that was parted out, the engine appears like it sat for a bit. I changed the plugs, wires cap and rotor, under the cap did not look bad the rotor did not come off easy, do ing. modules go bad from sitting or moisture or rust? I feel confident that it is wired correctly, orange battery, pink/black power with the key and light purple to crank side of the starter. The alternator has lead to the battery and then one to the junction block on the fire wall and one small lead to the factory gauge. The motor cranks fine build enough oil presure on cranking to power the pump. It just seems there is no signal for the 2 sec prime or to allow the injectors to pulse or spray. I did not wire the aldl yet so I can not read the codes, obd1 port was not on the harness. I am not sure where to go next, maybe pull the distributer and put in a new module and pick up coil or look in a new ecm. Thank you for putting up with my long and many posts.

Jesse
 
Dogman12 said:
The fuel relay has an orange wire for a power source, this is battery power so it is always hot. From my understanding the ignition module or the ecm should send a signal to the relay i think through a green and white wire ( from the ecm)and that should CLOSE the relay to allow power to the pump. The ecm I have is in a black case not silver so it may be after market it was an ebay purchase for 87-95 MT 350 truck or van I checked it to make sure it had a prom and it did. The engine itself came from an 89 blazer that was parted out, the engine appears like it sat for a bit. I changed the plugs, wires cap and rotor, under the cap did not look bad the rotor did not come off easy, do ing. modules go bad from sitting or moisture or rust? I feel confident that it is wired correctly, orange battery, pink/black power with the key and light purple to crank side of the starter. The alternator has lead to the battery and then one to the junction block on the fire wall and one small lead to the factory gauge. The motor cranks fine build enough oil presure on cranking to power the pump. It just seems there is no signal for the 2 sec prime or to allow the injectors to pulse or spray. I did not wire the aldl yet so I can not read the codes, obd1 port was not on the harness. I am not sure where to go next, maybe pull the distributer and put in a new module and pick up coil or look in a new ecm. Thank you for putting up with my long and many posts.

Jesse
Click to expand...

I think what the other guy was asking you is if you are getting 12V to the coil of the relay. I will assume you are not because the relay is new and it is still not working. Other than that I am worthless.
 
The stock relays are black.

I'm saying you should verify whether the problem is that the ECM wire is NOT providing the 12v to the relay (ECM or wiring problem) or whether the relay is receiving the signal, but just not turning on (relay problem).

It can only be one of those two problems.
 
I think you guys are probably barking up the wrong tree. If the fuel pump is turned on by the oil pressure switch, then the fuel pump relay is irrelevant.

It won't start with starting fluid, which means you have an ignition problem, not fuel.
 
If the fuel pump is turned on by the oil pressure switch, then the fuel pump relay is irrelevant.
Click to expand...

:doah:I missed the part about no fuel to the injectors at all.

It won't start with starting fluid, which means you have an ignition problem, not fuel.
Click to expand...

That sounds more likely now that I'm up to speed on my reading. :)
 
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